Color television system



NW. 18, 1947. N, GOLDSMITH 2,431,115

COLOR TELEVISION SYSTH Filed Aug. 5, 1944 2 Sheets-Shoot 1IllIIIIllIIIlllWllIlIIIllIIIIIIIIIIIIIHIHIHIHIlllllllll"IlllllllllllllllllllllIllllllllllllll|IIllIlllIlllllIIIllllllllllllllllllllllllmll mum:munmuummnmumnnmmu IALFREDN-GOIDSMITH.

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Y- 1947. A. N.'GOLDSMITH 2,431,115

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monm Patented Nov. 18, 1947 UNITED STATES PATENT OFFICE COLOR TELEVISIONSYSTEM Alfred N. Goldsmith, New York, N. Y.

Application August 5, 1944, Serial No. 548,240

27 Claims. 1

This invention is directed to television systems and is particularlyconcerned with improvements in electronic forms of television systemsmaking use of cathode ray electro-optical image producing devices.

In its preferred embodiment, the invention is concerned withimprovements in forms of apparatus of the type above stated whereelectro-optical images are made visible in colors closely approximatingthose of an original subject or scanned image. The image production insystems of this character is carried forward by socalled additive colorcombination method. To this end, provision is made for additivelycombining two or three, or even more, selected color components. Byrelating the color components in suitable manner and through suitableregistry of the separate images a group of luminous color componentimages result, where the several individual component color imagesclosely approximate the color separation images of the original in theseveral selected colors, and the complete image which results from theadditive combination provides a reasonably acceptable approach to thenatural overall luminous color density and color gradations of theoriginal image.

By two concurrently filed applications for Letters Patent entitledrespectively Color television, Ser. No. 548,238, and Multicolortelevision systems," Ser. No. 548,239, this applicant has disclosed twoforms of color television systems wherein provision is made for bothscanning and reproducing images in substantially their natural colors.While certain portions of these applications will have reference to thepresent disclosure, as will herein after be pointed out, the

present invention is concerned primarily with a means for producingcolor television images as electro-optical image reproductions on asingle luminescent or fluorescent target or screen provided at one endof a cathode ray image producing tube.

Further, the invention is concerned with the provision of either one ortwo or three, or more, related and suitably controlled scanning electronbeams for producing in registry the several component color images of aseries to form additive color image representations within the cathoderay tube.

In the present form a camera the invention is concerned primarily withcontrolling circuits operating in conjunction with a cathode ray tubehaving a viewing target area formed of a great many long narrow stripsof luminescent material arranged closely adjacent each other, A form oftube having a laminated color-striped target area formed from suitablecompounds which luminesce in desired selected component colors has beendisclosed in United States Patent No. 2,310,863, granted on February 9,1943, to H. W. Leverenz. According to the disclosure in the Leverenzpatent, which may be referred to herein for the purpose of illustratingone convenient method of target formation, a tricolor image may beproduced to provide tricolor additive image pro-1 1:;- tion through theuse of luminescent compounds intended to produce light under electronbeam activation in three selected component or primary colors, such asred, green, and blue. As disclosed by the Leverenz patent, the redluminescent efiects may be achieved by a target formation of chromiumactivated aluminum berylliate or zinc cadmium sulphide activated withsilver. achieved by providing alpha willemite activated with manganeseand zinc cadmium sulphide activated with silver. Lastly, the blueeffects may be caused to result from electron beam activation of atarget area formed from silver activated zinc sulphide, zinc silicateand zirconium silicate. The particular luminescent compounds hereinchosen for illustration are all disclosed in the Leverenz patent abovenamed, as well as the general method to form the laminated screen and,per se, form no part of the present invention.

The present invention is primarily concerned, therefore, with ways andmeans to improve the operation of such systems and to provide controlswhereby the various color target areas may be activated in the desiredsequence to produce the multicolor image representations,

In a preferred form of operation of such a system, the target area ofthe tube, which is impacted by the scanning electron beam, is formed asa laminated or superficially color-striped structure, with the combinedwidth of various laminated areas or longitudinal strips being such thatthe target sequence providing the red, the green, and the blueluminescent effects, for instance, shall all be confined within thewidth of a single normal width scanning trace, or even in a fractionthereof. Thus, for reference purposes, each of the strips or laminationsfrom which the complete target is formed is to be considered as being nowider than A; that of the normal scanning trace. To practice the methodand operation herein disclosed, the scanning electron beam, which is toproduce activation of the target, shall have a cross sectional area nowider, in the direction of travel, than the width of each individual Thegreen luminescent eilects may be strip. However, the height or lengthdimension, for instance, of the scanning electron beam may be greaterthan its width and may approach, or even equal, the width of onecomplete'scanning trace, which leads to the formation of a rectangularor elliptical scanning spot. Furthermore, according to the presentinvention, provision is made so that the scanning beam or beams whichproduce the difierent color electro-optical images shall be active onlyat times when sweeping or traversing the particular related colorluminescent strip which is to produce the desired component or primarycolor image for combination with the other images to produce thecomplete fluorescent or luminescent combination, adding together to formthe complete color image.

Various ways by which this control of the beam and the recording may beachieved are possible,

but the application will set forth, as one of the examples of suchcontrol, a system by which the deflected scanning beam or beams arecontrolled by a saw-tooth wave overcoming suitable biasing voltages sothat the recording on difierent color strips or laminations ofthe targetis possible.

Various modifications may be made whereby the phase of the controllingsawtooth wave is adjusted by suitable non-frequency discriminative meansso as to shift thereby theactive point or active location of thescanning spot appropriately in order to provide the desired degree ofregistration on any component color. Thus, by the use of suitablebiasing control means, the actu-' ating electron beam serving to producethe separate color images may be so controlled that successive effectiveregistrations or impacts are located upon like color responsive areas ofthe target. The time and place of activation of the respectivecomponent-color scanning electron beams are thus individually andaccurately controllable. In the case of simultaneous multicolorrecordings, the successive impacts of the scanning beam follow, from oneto another of the component colors in any desired sequence, but the beamcontrol is successively switched from one controlling source to anotherso that the effect of simultaneous scanning of multicolor images isachieved by means of a uniformly moving scanning beam which isequentially controlled as to its intensity. The correct phaserelationship by which the video signals produce the desired colormarkings or recordings is so controlled that the signal modulatedelectron scanning beam traverses the desired component color strip orlaminated area of the target in the desired manner.

The invention is also of such nature that simultaneous scanning of thestriped or laminated target area may be achieved by a plurality ofindependent scanning beams each signal controlled or modulated by oneonly of the video signals representative of the several componentcolors. A system of this character utilizes at least two scanningelectrons which impinge obliquely upon the target area. Compensation forthe angle of impact is provided by way of special deflection controlintroduced along with the normal deflection wave operative on the usualelectron beam deflection means. All foreshorteningeffects of red tracedraster area are removed readily by one modification of the deflectionwave and all lengthening effects are removed by a'diiferent or oppositemodification of the deflection of the beam. Systems to accomplish thistype of control efiect are disclosed in my above mentioned concurrentlyfiled patent applications and, accordingly, are not discussedherein inany great detail.

Accordingly, it becomes an object of this invention to provide animpacted target surface within an electro-optical image producing tubewhich shall have produced thereon a plurality of component color imageswhen activated by one or more suitably controlled scanning electronbeams.

Another object of the invention is that of providing a system oftricolor or mutlicolor television image production wherein the imagesresult in a plurality of chosen component colors which may be additivelycombined to produce a color image viding improvements in colortelevision image producing systems by which television images insubstantially natural colors may result with a simplification of theimage producing apparatus; with a reduction in the number of componentparts required by the installation; with a greater cheapness ofinstallation, and yet with a higher degree of operational efficiency.

Other objects and advantages become apparent and will at once suggestthemselves to those skilled in the art when the following description isread in' conjunction with the accompanying drawings, wherein:

Fig. 1 represents conventionally a section of a laminated target andshows, in schematic form, the scanning direction and scanning area ofthat target;

Fig. 2 represents a modification of the arrangement of Fig. 1, insofaras the general form of scanning is concerned;

Fig. 3 represents conventionally, by the portions a, b and 0 thereof,three separate controlled waves for influencing the scanning beam andfor controlling the cycle of operation;

Fig. 4 schematically represents the general method adopted forsimultaneous multicolor scanning of a target area in a tricolor system;

Fig. 5 diagrammatically represents one form of control system forutilizing the scanning arrangements of Figs. 1 or 2;

Fig. 6 represents a modification of the arrangement of Fig. 5 andprovides a difierent form of signal scanning beam control; and

Fig. 7 schematically represents one form of amplifier and limitercombination suited for use with a system of Fig. 5.

Considering now Fig. l of the drawings, there has been disclosed asection of a target area i l intended for use Within a cathode ray,image producing tube of substantially known configuration. The tube, perse, is not shown for reasons of simplicity, but it will be understoodthat the target area, i I is positioned either as a separate element atthe end of the tube or that the several striped or laminated sections ofthe target area i i are formed on the tube end wall in substantially thesame manner luminescent target areas are depounds or upon which aremounted the various luminescent compounds carrying strips or filaments.Such a target then may be provided within a tube envelope in a mannerclosely approximating that represented, for instance, by the tube shownin the above mentioned Leverenz United States Patent No. 2,310,863. I

For the purpose of explanation it will be assumed that the target II asshown by Fig. 1, is formed from a series of strips l3, l3, and 11,respectively, which are formed of such compounds or materials, asaforesaid, to produce. when activated by a scanning electron beam l9,luminescent effects in red, green, and blue.

The impacting electron scanning beam l9, which is developed within thecathode ray tube according to known methods, and likewise suitablyfocused to the configuration shown, may be of circular formation as itstrikes the target area. The beam deflection path is substantially thatshown by the arrow 2| and thus is transverse to the direction oflamination of the target area. For all practical purposes the width ofany one elemental area, or the height thereof, as it is formed inproducing the color television image, shall be assumed to be equal tothree strip widths, that is, equal to the combined transverse width ofthe strips l3, l5, and I! which is indicated immediately there beneath,by the dimension x. Likewise, if a substantially square elemental areais assumed, the height thereof, which is represented by the dimension y,will be equal to the width represented as 3st.

According to the method herein to be disclosed, the scanning spot I9, inthe position shown in Fig. 1, may be assumed to be recording and tracinga path on the target area I I such that the red areas only arerepresented, in which event the beam will move between impact area l9(shown in solid outline) and impact area l9 (shown in dotted outline)according to the directional path 2|. The dotted outlines between theimpacting areas I9 and I9 indicate a conventional suppression longdimension thereof representative of the height of any one elemental areaof the ultimately to be produced image, which has been assumed to be 11.The width of any one elliptical or rectangular scanning area will then,under the same assumed conditions, be equal to :c or, stated in terms ofheight, will equal one-third y. This narrow dimension corresponds alsoto the diameter of the scanning spot |9 as it impacts the target area l.

Where the operation and control is in accordance with the assumedsequential scanning pattern, the successive red areas will be impactedand the scanning spot having a shape such as the spot 20 will impactonly the red responsive areas l3 and will fall successively at areas 20,20', 20", and so on, along the scanning path 23. Electron beamsuppression takes place at areas along the scanning path 23, indicatedby dotted outline as separating the impact areas 20, 20', 20'', and soon. The manner of beam control to produce this suppression will later beexplained herein.

In the modified showing of Fig. 2, elliptical scanning spots have alsobeen represented for impact of areas |3, I3 and I! respectively,representing the red, the green, and the blue responsive sections of thetarget. However, in the arrangement shown by Fig. 2, it will be assumedthat three separate scanning spots 30, 40 and 50. all of ellipticalshape and of a type corresponding to the spot 20 shown by Fig. 1. aresimultaneously active so that the red, the green, and the blue imagesmay be produced at the impacted areas simultaneously. In thisarrangement, as the scanning spots move successively to different stripsor laminations of the target, they will follow the paths designatedconventionally as 3|, 4| and BI, with a complete scanning directionbeing constituted in a direction transverse to the laminations and asrepresented schematicall by the arrow. While the spot 30 moves along thepath 3|, for instance, to the next succeeding red responsive area; whilethe spot 40 moves along the path 4| to the next green responsive area;and while the blue spot 5|) moves similarly to the next blue responsivearea, the electron beam producing the spot should be suppressed so thatthe beam which impacts the area 30, for instance, shall not be effectiveon any green or blue responsive strip of the target but shall nextbecome operative in fact when the next red responsive target portion isreached. Provision is made for suppressing the scanning beam during thisportion of the cycle as will be explained in reference to Fig. 3.Likewise, the scanning beams producing the impact areas 40 and 50 arecontrolled and suppressed in a motion from strip to strip of this targetarea.

In the scanning operations as described in reference to Figs. 1 and 2,the general method of controlling the electron beam or scanning spot soas to produce the desired color fluorescent effect need not be discussed-in any substantial detail, for in principle the method of controllingelectron beam motion and the operational periods thereof has been setforth by my Patent No. 2,219,149, granted October 22, 1940, for"Television system. However, reference may be had to the showing of Fig.3 of this application for general understanding of the broad principlesof this method, although the aforesaid patent is to be considered alsoin this connection for such features as are shown therein.

Generally, a sawtooth wave, such as that represented by the waveformation 21, 29, 3|, 33, 35, 31, and so on, shall be utilized forcontrolling the cathode ray beam or scanning ray as it moves along thepath represented, for example, at 2| on Fig. 1. The general deflectionof the electron beam across the target area I may be controlledelectromagnetically or electrostatically, as desired, this being, perse, no specific part of the present invention and disclosed, forexample, in my above named patent.

Control of the electron beam as it passes between points I9 and I9, asin Fig. 1, or 20 and 20' in the same figure is provided by subjectingthe scanning beam to a control by a voltage wave of sawtooth formation,as above represented. In this ,way, the time period, which isrepresented along the abscissa of Fig. 3, by the distance betweenthepoints 21 and 3|, or 3| and 35, for instance, shall be regarded as thetime required normally to move the scanning spot of the red componentcolor image between the point [9 and the point l9, or, in other words,the time to move the scanning spot across three adjacent color stripsI3, l5 and I1. During all the time that the scanning beam is thus beingmoved in the direction represented by the arrow 2|, 9. negative voltageof constant value. represented, for instance, by the magnitude ofvoltage between points 39 and 4|, is added to the sawtooth wave 21, 29,3|, and so on, to produce thereby a new wave formation generallydesignated 43, 39, 29, 45, 41, 33, 49, 5!, 31, and so on. This wave,last named, then is impressed, in addition to the red component videosignal modulation, on the control electrode of the electron gun formingthe scanning beam so that during periods represented by time periods 63to 39 and 45 to 47, for instance, the scanning beam is just suppressed,while during periods represented in time between the points 39 and 45,for instance, the scanning beam is effectively released and exists withan intensity then controlled given the cutofi bias value 39, 4!, theamplitude of the sawtooth wave 2?, 29, 3i is of course determined andthe Video signal amplitude thus satisfactorily'controls the beamintensity between 39 and 45, during such time periods by the videosignal modulation.

It thus becomes evident that with an arrangement of this generalcharacter the scanning beam for producing the image in any one componentcolor (in a tricolor system) is active for approximately one-third ofthe total time, and inactive for approximately two-thirds of the totaltime, provided the subtractive biasing potential represented at 39, iiis properly selected. Furthermore, the scanning beam, under suchcircumstances, will become active to produce luminescent eifects in thetarget area it at exactly the correct time in the passage of thescanning beam over red responsive areas, while the beam is moved underthe influence of suitable deflecting fields along the path 2!, asindicated.

In general, to insure this accuracy and registration, where the scanningbeam is modulated during the time period 39 to 65, for instance, by thevideo signal, suitable phase shifting or phase adjusting elements shouldbe provided in the signal controlled channel, it being understood thatsuch phase shifting arrangements are non discriminative as regards tofrequency. Phase shifting networks of this type then serve to shift theactual points of impact of the scanning spot on the target or screenarea to the right or to the left in such fashion that the tive duringthe time period represented at 39, 65 shall register exactly with thecorresponding component color strip. Phase shifting networks of varioustypes are well known for this purpose and, accordingly, are notspecifically illustrated. Reference may well be made, however, to theinclusion of any suitable phase shifting network arranged in the controlcircuit of the electron beam in such manner as to effect the desiredfunction.

The deflection waves represented by curves b and c of Fig. 3 are similarin character to that wave above described and represented by curve a.However, the wave formations of Fig. 3 (b) and Fig. 3 (c) are markedsimilarly to the wave of Fig. 3 (a), but with prime or double prime,depending upon the curve. The Wave of Fig. 3 (b) is displaced relativeto the wave of Fig. 3 (a) so that it leads Fig. 3 (a) by 120 electricaldegrees and, accordingly, shall be regarded as controlling the imageproduction of the video signal of those areas of the laminated target II, which shall represent the blue color intensity, Likewise, the waveformation represented. by Fig. 3 (0) may be regarded as lagging the waveof Fig. 3 (a) impacting spot eflecr by 120 so that when the scanningelectron beam is influenced by the last named wave, the image productionshall be made to represent the green component color, so that if thescanning beam is active or signal controlled in the time period between39' and 45', for instance, a. blue color representation shall be formedon the screen while, it active or released in the time period between39" and 45", a green color representation shall result on the impactedtarget area ii.

Following a control of the ype hereinabove explained, further referencemay now be made again to Fig. 2 which represents a method whereby anycolor component scanning spot skips the width of two color strips beforereappear-lug, so that the scanning spot 30, for instance, moves whilesuppressed from the red fluorescent strip i3 to the next succeedingfluorescent strip i3, and so on.

A method of this character generally applies to simultaneous scanning ofall of the adjacent component colors so that all of the signalsrepresenting the selected color components are always simultaneouslyvariable, even though not all simultaneously utilized. Various ways toaccomplish scanning in this form may be provided within the scope of thepresent invention.

One method to achieve this objective is to have the single scanning spot30 of Fig, 2, for instance, controlled for a period corresponding to theperiod 39, d5, of Fig. 3 (a) of the red component color video signal.Then, this is to be followed by a control during the time periodrepresented at ll, 39', for instance, of the blue color componentsignal, and so on. Here it is unnecessary to show the means by which thered, the green, and the blue component color signals are commutatedelectrically by means of the method generally represented by Fig. 3, noryet the method by which these various signals may be briefly andserially applied in proper timed relationship to effect the desiredcontrol action, nor yet to illlustrate graphically the suitable durationof the signal control on the individual single scanning gun.

Another method by which the scanning pattern may be effective is toprovide within the scanning tube three separate electron guns, as shown,for instance, by the general form of tube represented in my two abovenamed concurrently filed patent applications. In a method where threeelectron guns, and consequently, three separate scanning spots of thetype generally represented by the spots 23 of Fig. l, for instance, or3d, 40 and 50, for instance, of Fig. 2, are provided, one of thescanning guns is arranged to project its scanning beam till of Fig. 4,for instance, in a plane as represented by the arrow immediately belowthe beam such that it strikes the target area it (such as along stripl3), substantially normally throughout the range of its motion ordeflection. The result is that a substantially rectangular pattern, suchas that conventionally represented within the rectangular area 53, 55,51, 59 is usually traced, where the aspect ratio of the produced imagearea or raster is of the order of the customarily adopted four to three.Similarly, the scanning beam 70 from one of the other two scanning guns(not shown) which may be assumed to trace the scanning spot 40representative of the green video signal modulation, will impinge uponthe target area H at a point very closely adjacent that at which thebeam 60 impacts the target, with theactual separation between the twospots 30 and 40 being of the order represented, for instance, by Fig.

' 2. With the scanning beam 10 emanating from to the side 53, 59 of therectangle, with the displacement therefrom to the right substantially asrepresented by the spacin between the red and the green responsive areasi3 and 15 of Fig. 2. Likewise, the scanningbeam 80 shall impact thetarget area II at a point such as that represented at 50 in'Fig. 2, andit will, accordingly, trace also a trapezium shaped area conventionallymarked 69, H, 13, I5, with the longest side H, 13 now being assumed tobe substantial y contiguous to the side 55, 51 of the rectangle R, butdisplaced therefrom by two strip widths to the right so as to form theblue color image. Then the shorter side 69, 15 shall be contiguous withthe long side BI, 61 of the rectangle G, but displaced therefrom to theright by the width of one color responsive strip.

To correct for this distortion. various methods and means were shown andparticular y described in connection with my copending applicationentitled Color telev sion, Ser. No. 548.238, filedconcurrently'herewith. and further detailed reference thereto need notbe made. Any foreshortening for lengthening of the border or boundaryareas of the formed image raster for any selected component color may bemodified through the addition of suitable correcting voltages orcurrents in the deflecting wave form which is applied to the deflectingcoils or plates for effecting an electro-magnetic or an electrostaticdefiection of a cathode ray beam within a tube.

Accordingly, for the purpose of this disclosure it should be understoodthat the desire is to provide a system wherein the image rasters tracedby all of the scanning beams 60, Ill and 80, tracing for instance, thered, the green, and the blue images, shall be corrected so as tocoincide substantially and be displaced laterally one from the other bythe width each of one-third of the maximum dimension of any one imagepoint.

If reference is now made further to the method of operation disclosed byFig. 3 which, for instance, might be suitable to control scanning beamssuch as those represented at 60, ill, and Bil of Fig. 4, there isincluded in the arrangement a suitable generator of sawtooth waves whichwill produce the waves 21, 29. 3|; 3|, 33, 35; 35, 31 and so on, asrepresented by Fig:3 (a) and, similarly the sawtooth wave formationsrepresented by Fig. 3 (b) and Fig. 3 (c). The period of the sawtoothwave, as represented by the time conventionally represented betweenpoints 21 and 3|, for instance, will be equal to the time required toscan three strips of the laminated target area Ii, that is, the stripsI3, i and I1. The scanning of these strips or laminations of the targetI i is assumed to be along a path transverse to the strips asrepresented, for instance, by 2!, so that the sawtooth waves occur at afrequency closely approximating or equalling one-third of the totalnumber of scanned strips or laminations per traversal of the scanningelectron beam or ray along any linear path.

To achieve the object of controlling the scanl0 ning ray or beam in thedesired fashion to produce tricolor image representations for instance,three separate sawtooth waves must be developed and these must be madeto be capable of adjustment to the correct phasal position to representthe correct color scanning with the phasing being as above stated 120electrical degrees from each other. The amplitude of the sawtooth wave,in each instance, shall be of such value that there can be added theretoa constant negative bias equal, in the case of tricolor images, toapproximately two-thirds of the peak amplitude. The

, resulting brief sawtooth peaks, so to speak, are

then arranged to be passed through an A.-C. amplifier of eitheraperiodic or non-frequency discrirninative character within the range offrequencies required properly to reproduce the sawtooth peaks. Ofcourse, as an optional arrangement the sawtooth peaks might be sentthrough "a limiter whereby they are converted essentially to squarewaves of a length equal to the time of scanning one elemental strip orlamination approximately, and then suitably sequentially phased. Thepeaked sawtooth waves or square waves then are preferably applied to anamplifier in the video signal circuit leading to the control electrodeof the image producing tube in such fashion as to release the cutofibias during the desired time period of operation, as represented by theselected sawtooth or square wave peaks.

Reference may now be made to the schematic diagram of Fig. 5 where asource of line frequency impulses is schematically represented at iii.The line frequency impulses so developed may be produced in any desiredmanner and preferably are triggered under the control of incoming linesynchronizing impulses, or the pulse source may be constituted by theactual received line synchronizing impulses. Signal impulses at thisfrequency are then supplied to an appropriate frequency multiplier unit83 in which they are suitably multiplied.

Generally speaking, the unit 83 consists of a plurality of stages inthat its object is that of developing impulses at multiples of the linefrequency which correspond to the number of image elements or pointswhich are to be produced within the raster traced by the scanningcathode ray beam.

In a system wherein thirty complete scannings occur per second, andwhere an image raster having four to three aspect ratio is produced with525 separate scanning lines, it will be apparent that, for purposes ofcalculation, each scanning trace or line may be assumed to be composedof 700 elemental areas or points. With the scanning beam being requiredto trace, in the production of each elemental point of the resultantimage, three separate component color areas, such as I3, [5, and IT, forinstance, it will be apparent that the frequency at which the sawtoothwaves energy, such as 21, 29, 3|, 33, 35, and so on, are developed,shall correspond to the line frequency multiplied by the number ofpoints per line, so that, in the illustrated example, frequencymultiplication of 700 to 1 may be assumed to take place within thefrequency multiplier unit 83. The unit is represented schematicallysince, per se, the circuits included do not constitute a part of theinvention and any well known form of frequency multiplier unit whichwill produce the same general form of output in the nature of pulses maybe utilized.

The output signals occurring at the multiple frequency and appearing inthe output of the frequency multiplier 03 are then supplied to asuitable sawtooth wave generator unit 85 for the purpose of triggeringit'and producing the sawtooth wave form of the general configurationrepresented, for instance, by any one of the curves of Fig. 3. Theoutput energy or voltage waves from the sawtooth generator 85 are thenpassed through suitable conductors 81 and 89 which connect withquarter-phase coils 9| and 93, with coil 9| being connected to theconductors 81, 89 I through a capacitor 90 so that a rotating field isdeveloped by the coils. Separate pickup 00115 95, 96 and 91, of whichthe schematic representation of Fig. 5 shows a proposed circuit for .oneonly of these coils, are located 120 electrical degrees apart from eachother within this electrical field.

In order to adjust the exact phase of the output of the coils 95, 96 and97! to a proper relationship with respect to each other and the severalcomponent color image reproductions which are instantaneously to beproduced in the luminescent strips I3, I5, I! of Fig. 1, for instance,which strips from the target area of the image producing tube I 00, theseveral coils 95, 96 and 9'! are accurately rotatably adjusted in thedirections shown by the arrows about a central point within the rotatingfield of the coils 9| and 93, The foregoing constitutes an additionalmanner over that herein before suggested for producing the several waveforms represented for instance, by the curves a, b, and c of Fig. 3,thereby to induce into the load circuits connected to the several pickupcoils 95, 96 and 91, electrical waves bearing the desired phaseairelationship with respect to each other and at the same time being ofthe desired wave configuration.

The method shown for providing the sawtooth electrical waves of theappropriate frequency and of appropriate phaseal relationship relativeto each other is merely one of several which may be adopted for thepurpose of this invention. Accordingly, the form shown is to beconsidered as illustrative and it will be realized that alternativeelectrical methods, already known in the art, may be used within thescope of the invention.

The output energy from the pickup coil 95 is suitably amplified in anamplifier IOI which may be of any desired and conventional design, suchas is well known in the art. Output energy from the amplifier I is thensupplied to a further aperiodic a p fi r I03 also of conventionalcharacter. The output signals passing from amplifier I M to theaperiodic amplifier I03 are supplied through a potentiometer I05 towhich the variable tapping point I01 leading from amplifier IN isconnected.

The drawings illustrate a biasing source I09 in the form of a usualbattery arrangement so poled that a suitable negative bias, representedin Fig. 3 by the line 39, 4I and in the wave diagram is effective uponthe aperiodic amplifier I03 an electrical wave which may be consideredas being the wave form 39, 29, 45, 41, 33, 49, 5i, and so on. This isnot however directly applied to the video control grid of tube I I,

This activating wave form is then further distortionlessly amplified inthe aperiodic amplifier I03 until this wave form may be considered, forillustrative purposes, as corresponding to the wave form represented inFig. 5 adjacent that portion of the conductor between the aperiodicamplifier I03 and a limiting device II3. In the limiting device I I3,desired limiting effects may be achieved whereby in the output agenerally square wave formation, diagrammatically represented at H5, H1in the output of the limiter H3, may result.

Figure 7 shows one form of circuit to illustrate suitable amplifier andlimiter units for use as the elements I03 and H3 of Figure 5. In thisarrangement, the incoming signals which overcome the biasing voltageapplied by the source I09 are fed to the input of the wideband amplifiertube I02. This tube is preferably, though not essentially, one of theso-called pentode variety. Usually, the tube is self-biased, asindicated. The output circuit of the tube may include the peaking coilI04 to prevent a falling response char acteristic with increasingfrequency of the input signal. The usual load resistor I06 is connectedin series with this peaking coil to a suitable source of voltage notshown. Output signals which appearacross the load resistor I06 are thensupplied, by way of the condenser I08 and the resistor I I0, to thecontrol electrode of a clipper or limiter tube II2. This tubepreferablyhas its cathode connected to ground as well as the grid resistor II4,which connects between the junction of the coupling condenser I08 andthe input resistor I I0. With this arrangement, it will be apparent thatthe resistor H0 functions to prevent the grid from going very positiveduring the peak input pulses, such as those indicated in Figure 5. Whenthe grid does become slightly positive, grid current flows through theresistor IIO, as well as the grid resistor H4, and a negative voltage isdeveloped which acts as the bias to limit the positive voltage on thegrid. During periods when peak pulses are not present, electrons in thegrid condenser I08 flow to ground through the grid resistor I I 4 andset the bias level. The time constant of the condenser I08 and theresistor I I4 is usually, large compared with the period of the inputvoltage. The square wave output signals from the tube H2 are thensupplied to the conductor I29,- as indicated more particularl by Figure5. The dotted outline rectangles I03 and H3 show the corresponding partsin Figure 5.

It is, of course, optional whether or not the limiter I I3 be used, forthe output of the aperiodic immediately adjacent amplifier IOI as thevalue :1: must be overcome before any wave energy is applied to theaperiodic amplifier I03. Thus, a biasing voltage which may be assumed tobe equal to two-thirds or the peak amplitude of the sawtooth wave outputfrom amplifier IOI may be azsumed to be effective in the aperiodicamplifier For illustrative purposes, in Fig. 5 the wave form shown torepresent the output from amplifier IN is assumed to have the samecharacteristics as that wave form represented by Fig. 3 (a), and,accordin ly, like numerals refer to like operations of the electricalwave assull'ifi r Thus, there amplifier I03 may be assumed to be thecontrolling wave where desired, but for practical consideration it isusually convenient to depend upon the square wave form illustrated H5,H1, and so on.

The amplitude of the square wave I I5, I I1, and so on, is usually madegreater than the cut-off bias of the controlled tube later to bedescribed, so that the tube controlled may be carried to a cut-off stateunder conditions when signal is lacking in the amplifier channelassociated with pickup coil 95, but which will become effective duringsignalling periods.

In order that images may be produced on the target area II of theimage-producing cathode ray tube I00, an electron beam, conventionallyrepresented at H9, is developed within the tube between the cathode I 2|and the anode I23 for instance, and this beam is then directed towardthe target area II in the'well known manner. Control of the developedelectron beam or cathode ray H9 is effected by means of a controlelectrode or grid element I25 usually Placed Within the tubeintermediate the cathode and the anode and formed as a part of the beamdeveloping electron pin.

Biasing voltages are applied to the control electrode I25 from thebiasing source conventionally represented at I21. Accordingly, with thebiasing source I21 being poled relative to the control electrode I25 soas normally to carry'the control electrode negative, it is apparent thatthe electron beam II9 will normally be suppressed in the absence of sometriggering voltage where the bias voltage supplied fromthe source I21 isequal to a cut-off value for the tube.

Thus, it may be assumed for illustrative purposes that the electron beamdeveloped within the tube I III) is normall suppressed and ineffectiveto reach the screen or target I I by the action of the biasing sourceI21. However, due to the output from the limiter II3 being connected tothe control electrode I25 through conductor I29 and the biasing sourceI21, it becomes apparent that during periods represented by the time ofoccurrence'of the square wave pulses H and II1, for instance, in theoutput of the limiter IIB, the biasing effect of the biasing source I21may be overcome and electron beam II9 duly formed.

Thus, the signal output from the limiter II3 serves to cause theelectron beam or cathode ray I is alternately to be formed and thensuppressed,

' with the period of suppression being twice as long in the exampleillustrated as the period of beam formation.

Simultaneously with the control of the formation of the electron beam H9under the influence of the output signal or square wave pulse from thelimiter H3, a video signal is assumed to be supplied at the inputterminal I3I and to be fed through conductor I33 to the bias source I21and the control electrode I25. If the video control signal (which isassumed to be developed from any suitable receiver which is not shown)applied at the input terminal I3I is to represent a red version of theimage, then it is apparent that during periods of time that the electronbeam H9 is formed (that is, during time periods corresponding to theduration of the pulses II5 and H1 for instance), the formed electronbeam will be modulated under the control of the red video signal. 7

Suitable means for deflecting the formed electron beam I IS inbi-directional paths across the target area II to form the desired imageraster are provided by way of the conventionally represented deflectingcoils I35 which are customarily formed in a yoke surrounding the tubeneck.

It is of course evident that the showing of Fig. 5 is purelyillustrative of a conventional means of controlling an electron beam ina tricolor image-producing system insofar as the control of one of thecomponent color images only is concerned. For the control of the twoother color components of the tricolor image-producing system, and forthe purpose of showing more directly the relationship of all thecomponent colors with respect to each other, reference may be made moreparticularly to the showing of Fig. 6, in that the method illustrated byFig. 5 is more particularly applicable to the control of a herein byFig. 4) which each direct an electron beam toward the target area II.Thus, Fig. 5 illustrativeiy represents the control or one only of theproduced electron beams; the control of the other two electron beams, i.e., for instance, the electron beam forming the green and the blue colorcomponents of the complete tricolor image, may be assumed to becomeefl'ective under the influence of the signal generated in the pickupcoils 86 and 91, which are each positioned 120 (electrical degrees) outof phase relative to the pickup coil 85.

Control of the auxiliary electron beams. such for instance as thoserepresented at 10 and II for the green and the blue images, may then beassumed to be developed by way or control systems, which arecounterparts of that hereinabove explained in connection with theassumed red color control as derived from pickup coil 95, except thatthe 120 electrical degrees phase displacement exist between theirrespective outputs as previously described.

Referring now, however, more particularly to Fig. 6 for a description ofa system wherein a single electron beam forming means only is utilizedto direct a formed electron beam or cathode ray toward animage-producing target or screen area II, there has been shown a controlefiected through a series of independent amplifier units. Theseamplifiers may be represented at I for the red signal, at I43 tor thegreen signal, and at I45 for the blue signal. Each ampliher is purely ofconventional design and corresponds to those used customarily as theoutput amplifiers in the usual forms of known television image-producingarrangements.

To eifect a control of the amplifier units Ill, each may be provided inthe initial stage, for instance, with a multi-grid control tube, to theinner grid of which a biasing signal is customarily applied and to anouter grid to which a video modulation signal of the correspondingcomponent color is customarily applied. It can be assumed the videosignal representative of the red component color image is now applied atan input terminal conventionally represented at I 5|, and then directedby way of a conductor I53 to the amplifier unit MI. The amplifiers HI,I43, I45 must be capable of amplifying substantially distortionlessly atfrequencies at least as high as the activating impulse frequency.

The activating signal. which will correspond to the square wave controlsignal shown as appearing in the output of the limiter II3 (Fig. 5 forexample) is then applied to the activating signal input terminal I 55,and then supplied by way of conductor I51, and bias source I59 to theinner control electrode of the first tube of the amplifier unit Ill. Thebias battery or bias source I59 then may be assumed to be of magnitudesufficient normally to drive the first amplifier tube of the amplifierunit Ill to a cut-oil state in the absence of any control signaladequate to overcome the effect of the bias source.

The control signal applied at the terminal III, which signal isrepresented by the square wave f l5 output of the limiter such as H3, isof the magnitude suflicient to overcome the effect of the bias sourceI59 driving the amplifier I to cutoil'. Accordingly. during periods oftime when square wave pulses such as H5 or II! are applied at terminalI55, the amplifier MI .is brought to an operative state and the videosignal applied at terminal I5I is then capable of controlling theamplifier and developing a suitable controlled signal output therefromwhich is applied through the output conductors IBI and I63 to an outputterminal I65 herein assumed to be connected to the control electrode I25of a tube such as that shown by Fig. 5.

This last named connection may be efiected through the intermediary ofany suitable biasing means for the image producing tube. I which willinitiate an optimum state of operation therein.

So that the green image representation is produced to follow in sequencethe red image production, the video signal representative of green iscontinuously applied to the video signal input terminal I6! and directedto the amplifier I43 through a. conductor I69. This amplifier I43 is ofthe same general character as that above explained in connection withamplifier lit for the red signal channel. So that the amplifier I 4!shall normally and in the absence of a control signal pulse be biased toa cut-ofi state, a biasing source *III is connected intermediate theamplifier and an activating signal input terminal W3. A. control pulseof the general character of that shown, appearing in the output of thelimiter H3 in Fig. 5, is assumed to be applied at the activating signalinput terminal I13, it being understood however, that the activatingsignal is delayed 120 electrical degrees in phase relative to thatsignal applied at the activating signal input terminal I55 abovementioned.

Accordingly, during periods of time when the activating signal appliedat the terminal I13 causes the amplifier H433 to become active over theefiect of the 'cut-ofi bias applied from the source H I; any videosignals which are applied at the input terminal I61 will be suitablyamplified and appear in the output conductor I75, from which they aresupplied to conductor I63 and caused to control the modulation of asuitable electron beam through the control electrode of the cathode raytube which is connected to the terminal I55.

With the control system efiective on the green channel being delayedwith regard to the red signal by 120, it is apparent that the greensignal becomes effective to modulate the developed cathode ray beam at atime when the red image signal amplification is interrupted, so that thesequence of operations brings the red signal modulation to be followedby the green signal modulation.

The remaining one-third of the complete cycle thenis to be effected bythe blue image signal production, which is brought about by supplyingthe blue video signal to the input terminal ill and directing itto theamplifier I45 through conductor I19. A biasing source I8I, connectingintermediate amplifier H and the activating signal input terminal I83,holds the amplifier I45 in operation or at a cut-off state duringperiods of operation of each of the red and the green signal amplifiersMI and I 43. But where the activating signal applied at the inputterminal I83 is delayed 240 electrical degrees relative to the signalapplied at the terminal I35 and is delayed 120 electrical degreesrelative to the signal supplied at the activating signal input terminalI13, and all of the activating signals are of the same time duration, itis apparent that amplifier I45 will follow the operation of amplifierI43 and its output signal may then be supplied by Way of conductors I83and I63 to take over the control of the image production in the tubeI00; after which the complete cycle above will be repeated.

In this way the eifect of image production, of the general typeillustrated by Fig. 2, is achieved with the production of the imagepoints 30, it and 50 for instance being determined in accordance withthe operative periods of the red, green and blue amplifiers I4I, I43 andI45; and the blanking periods between successive like image colorrepresentations, such as those periods represented in Fig. 2 at 3|, 4|and 5| for instance, are determined by the periods during which thebiasing sources I59, Ill and I8I for instance hold the amplifiers I4I,I43 and I45 in a cut-ofi state.

An arrangement of the type last described is, of course, one in whichthe formed electron beam M9, for instance, is continually subjected tothe action of deflecting period tending to cause it to trace a sequenceof lines across the target area II, and then after each line is tracedthe beam is moved downwardly for instance to trace the next succeedingparallel trace. Obviously the traces across the target area I I may besuch that the rapid component of motion is horizontal (the presentcustomary method for scanning), or vertical as desired. Further, eachcomponent-color video signal is active and in control of the scanningbeam at times when that beam impinges on a fluorescent line of thecorresponding color. As previously stated, adjustment means may beprovided to secure initially and to maintain the cor respondingregistry.

An arrangement of the type last described, and particularly referred toby Fig. 6, of course does not necessitate the elaborate area distortioncorrections which would be required in the case of a multi-beam tube ofthe character noted by Fig. 4, and the application of a series ofcontrolling or activating signals, such as those derived from thepick-up coils 95, 96 and 91, being made to become efiective at the inputterminals I55, I13 and I 83 causes the effect of electronic switchinbetween the successive controlling colors.

In the foregoing description and in the claims to follow it will beunderstood that reference to the term element may mean either a linearor a point element. Accordingly, an element in an area having at leastone extremely small dimension which is significant and relevant to thedescribed process so that a point or element may, for generalconsideration, be regarded as a minute circle, a square, a rectangle, anellipse or the like, having the major dimension of minute size. Furtherin this connection, it will be understood that a linear element isessentially a narrow strip and is usually straight. It is to beconsidered as having one finite dimension along its length and oneextremely minute dimension (theoretically infinitesimal), which may beregarded as being along its width. In this way the significant andrelevant dimension of a linear element as related to television scanningmust be its minute width so that, in effect, a linear element acts andappears as a linear assembly of a multiplicityof point elements.

Further, in the foregoing description it might be assumed, at least byinference, that the target strips across which the electron beam is toscan are each of equal width or substantially such thereso. When thetarget strips are actually of equal width, it will be appreciated thatthe luminescent compound coatings thereon must be of such character thatfor any given beam current and any given period of beam impact on eachstrip of the target, intensities of light will be developed in theseveral chosen component or primary colors which will summationally addto white or shades of neutral gray. When such is the case, then itbecomes evident that the pulses controlling the times of successive beamformation in the case of multiple beam tubes, or signal modulation ofone beam by signals representative of one color in the case of a singlebeam tube controlled in sequence by signals of the several componentcolors, will be delayed in phase with regard to their active periodsrelative to each other by a phase delay equal to 21r/C, where representsthe number of component colors in the color series.

However, it sometimes happens that the luminescent materials orcompounds which produce light in the several component colors such asthe red, the green and the blue, for instance, do not always developlight with relative intensities meeting the condition for an additiveefiect of white or neutral gray. Therefore, to compensate for suchvariances in order that white or gray light may result from the completecolor series, it occasionally becomes necessary or at least desirable tovary the Width of the several strips of each color strip series relativeto each other, or simultaneously to vary the current in the diiferentbeams of a multiple beam system, or the beam velocity or current fromtime to time in a single beam system, so that substantial color equalityis produced. Under these circumstances, if a system of additive color beassumed where the red, the green, and the blue follow each other in sequence to form one color series, then it may be assumed that the widthof the red strips will each be equal to dr, the width of the green strip1 being represented by dg, and the width of the blue strip beingrepresented by db. Now, under such circumstances, the phase displacementof the control pulses hereinabove described for the several beams or thepulses for controlling the time periods when the impressed modulationsignal energy is effected on one beam may be considered, for instance,as being zero (0) for the red beam; but, for the green beam, under thesecircumstances, it will be displaced from the red by an amount which isequal to while the blue beam will be displaced from the red beam by anamount equal to r+ g+ i) The foregoing will be apparent in view of thefact that the phase displacement now becomes determined in accordancewith the tim required for one or a multiplicity of electron beams toscan or traverse each of the several strip elements in directionstransverse to the strip length and then to enter upon the next adjacentstrip.

Accordingly, for the purpose of this invention,

as it is defined in the claims to follow, it will be understood thatreferences to the phase delay shall be broadly considered on the basisthat the strips are actually of equal width notwithstanding the factthat this condition may not always be prevalent; and further within themeaning of the claims herein presented, it will be appreciated thatreference to the periods of beam formation and beam suppression shall bebroadly construed as applicable to systems with equal width targetstrips as well as to systems with unequal width target strips. Likewise,references to the method and/0r means of synthesizing the modulationcontrol with beam impact or the concatenation of the scanning with amodulation control shall be such that the proper impressed signal or theproper impacting beam strikes the target at areas to produce the desiredcolor response.

While the invention has been described in its preferred forms, it is ofcourse to be understood that many and various modifications may be madewithin the spirit and scope of what is hereinabove set forth, and Itherefore believe myself rightly to be entitled to make and use any andall of these modifications as fairly suggest themselves from what hashereinabove been set forth.

Having now described the invention, what is claimed and desired to besecured by Letters Patent is the following:

1. A color television system comprising an electron tube having abuilt-up target area formed as a repeating series of strip-like elementswith the target elements of each series being of materials adapted tofluoresce upon electron beam impact in each of a predetermined number ofcomponent colors to provide additive color images, means to deflect andconcurrently modulate the electron beam under the sequential control ofseparate video signals equal in number to and representative of each ofthe selected component colors of the additive color system to provideintensity control of the color response in each color, means fordeveloping beam control energy having a predetermined relationship tothe line frequency at which produced color images are to be developed tolimit the periods of active beam response and suppression, means to generate from the control energy a series of control pulses out of phasewith respect to each other by predetermined amounts, and means forutilizing the said phase shifted pulses to control the time periodsduring which signals representative of the several component colors areapplied to control the image production.

2. A color television system comprising an electron tube having abuilt-up target area formed as a repeating series of strip-like elementswith the target elements of each series being of materials adapted tofluoresce upon electron impact in each of a predetermined number ofcomponent colors to provide additive color images, mean to develop anelectron beam, means to deflect the electron beam relative to the targetarea to cause the beam to trace a scanning raster thereover,

means to modulate the deflected electron beam in sequence under controlof video signals representative of each of the selected component colorsof the additive color system to provide in sequence intensity control ofthe beam in different color response, means for developing beam controlenergy having a predetermined relationship to the line frequency atwhich produced color images are to be developed to limit the periods ofactive beam response, means to generate from the control energy a seriesof control pulses out of phase with respect to each other bypredetermined amounts and means for utilizing the said phase shiftedpulses to control the time periods during which signals representativeof the several component colors are applied to control the imageproduction.

3. In a tricolor television system wherein is included an electron tubehaving a target area formed as a repeating series of elongated stripsadapted to luminesce, under electron beam impact, to produce lighteffects in the several component colors of a tricolor additive system,and

wherein a plurality of electron beams equal in direction transverse tothe lengthwise dimension of the elongated strips and a relatively slowdeflection being in a direction lengthwise of the strips, generatingcontrolling wave energy for controlling the time of formation andsuppression of each of the deflected electron beams, shifting thephaseal relationship of the developed wave energy for controlling theplurality electron beams so that the beams are formed in sequence toreach the impacted target area so that each formed electron beam impactsstrips of one character only in the series and remains inactive duringremaining periods of deflection transverse to other predetermined colorimage producing strips of the target, and modulating the formed electronbeams by signal energy representative of the coordinated color responseindications developed upon the target area, by the impacting beam.

4. A color television system comprising an electron tube having abuilt-up target area formed as a repeating series of strip-like elementswith the target elements of each series being of materials adapted tofluoresce upon electron impact in a predetermined number of componentcolors to provide additive color images, means to develop an electronbeam and deflect it to trace a scanned raster on the target, means tomodulate the deflected electron beam under control of video signalsrepresentative in sequence of each of the selected component colors ofthe additive color system to provide intensity control of each colorresponse, means for developing beam control energy having apredetermined relationship to 20 of a single color response only withthe scanning being in a direction transverse to the strip elements andmeans to restrict the scanning of the target by individual electronbeams each to areas of a single color response only.

6. Electronic apparatus of the class described comprising a supportsurface element, a multiplicity of elongated coated and color responsiveimpact strips each of a sub-elemental width and each secured to saidsupport surface element, said coatings of the impact elements of thesub-elemental width strips being of a plurality of materials adapted toeffect a response under electron impact which closely approximatespredetermined colors of a multicolor additive color system, the saidgroupings of the said sub-elemental width strips being such thatsubstantially at least one coated element of each color response isincluded within an area corresponding to an elemental area of finitesize, and means for developing a plurality of modulatable electron beamseach adapted to be directed toward the said support surface element toscan individually the sub-elemental width coated strips of a singlecolor response only with the scanning being in a, direction transverseto the strip elements.

the line frequency at which produced color image raster is developed,means to utilize said control energy to limit the periods of active beamresponse by generating from the control energy a series of controlpulses out of phase with respect to each other by predetermined amountsand means for utilizing the said pulses to control the time periodsduring which signals representative of the several component colors areapplied to control the image production.

5. Electronic apparatus of the class described comprising a supportsurface element, a multiplicity of elongated coated and color responsiveimpact strips each of a sub-elemental width and each secured to saidsupport surface element, said coatings of the impact elements of thesub-elemental width strips being of a plurality of luminescent materialsadapted to produce a color response under electron impact which closelyapproximates predetermined colors of amulticolor additive color system,the said groupings of the '7. Electronic apparatus of the classdescribed comprising a support surface element, a multiplicity ofelongated coated and color responsive impact strips each of asub-elemental area width and each secured to said support surfaceelement, said coatings of the impact elements of the subelemental widthstrips being of a plurality of materials adapted to effect a responseunder electron impact which closely approximates predetermined colors ofa multicolor additive color system, the said groupings of thesub-elemental Width strips being such that substantially at least onecoated element of each color response is included within an areacorresponding to an elemental area of finite size, and means fordeveloping a plurality of modulatable electron beams each adapted to bedirected toward the said support surface element to scan individuallythe sub-elemental width coated strips of a single color response only,

8. In combination with electronic apparatus of the class describedcomprising a support surface element and a multiplicity of elongatedcoated and color responsive luminescent impact strips each of asub-elemental area width secured to said support surface element,said'coatings of the impact elements of the sub-elemental width stripsbeing of aplurality of materials adapted to luminesce under electronimpact which closely approximates predetermined colors of a multicoloradditive color system and the said groupings of the said sub-elementalwidth strips being such that substantially at least one coated elementof each color response is included within an area corresponding to anelemental area of finite size, means for developing a plurality ofmodulatable electron beams equal in number to the number of separatecolor luminescent impact strips in each series and each adapted to bedirected toward the said support surface element to impact the surfaceapproximately orthogonally and each to scan individually thesub-elemental width coated strips of a single color response only withthe scanning being in a direction transverse to the strip elements, andinterlocked and interrelated means to modify the uncorrected scanningpath for each beam to establish uniformity in path length separatelyfrom the deflection,

thereby to establish registry of pattern of each scanning.

9 Electronic apparatus of the class described comprising a supportsurface element, a multiplicity of elongated coated and color responsiveimpact strips each of a sub-elemental width and each secured to saidsupport surface element, said coatings of the impact elements of thesub-elemental width strips being of a plurality of luminescent materialsadapted to produce a color response under electron impact which closelyapproximates predetermined colors of a multicolor additive color system,the said groupings of the said sub-elemental width strips being suchthat substantially at least one coated element of each color response isincluded within an area corresponding to an elemental area of finitesize, and means for developing a plurality of modulatable electron beamseach adapted to be directed toward the said support surface element toscan individually the sub-elemental width coated strips of a singlecolor response only with the scanning being in a direction transverse tothe strip elements.

10. In a tricolor television system wherein is included an electronimage producing tube having a target area formed as a repeating seriesof elongated strips adapted to luminesce, under elec-. tron beam impact,to produce light in the several component colors of an additive tricolorsystem and wherein an electron beam is developed within the tube forscanning the component color producing strips along paths transverse tothe strip length at a relatively high rate and along the length of arelatively slow rate to trace an image raster, the method of producingcyclically additive color images which comprises supplying modulationsignal energy representative of each of the selected component colors tomodulate the developed electron beam, continuously applying to theelectron beam control a series of biasing voltages normally tending tonullify the modulation effect of signals supplied, generating controlwave energy pulses, producing from the control wave energy pulses aplurality of phase shifted variances thereof with the phase shiftbetween the different signals being equal to 21r/C where c is the numberof component colors in the additive system, and utilizing the phaseshifted variances in the control wave energy pulses for sequentiallyovercoming the biasing efiect on each of the impressed component colormodulation signals so that the component color signals sequentiallymodulate the developed electron beam and luminescent effects in theselected component colors on the target area are developed with theintensity thereof controlled in accordance with the applied signalenergy. 4

11. A tricolor television system wherein is included an electron tubehaving a target area formed as a repeating series of elongated stripsadapted to luminesce in the several component colors of a tricoloradditive system when the component color sections are activated by anelectron beam impacting thereon and wherein a plurality of electronbeams equal in number to the number of different component colorproducing strips in the series are developed with each electron beambeing adapted to impact the target,

the method of producing additive color imagesv on the target area whichcomprises deflecting each of the developed electron beams simultaneouslyacross the target in directions substantially normal to the elongateddimension of each of the strips of the luminescent material, con- 22catenating the deflections so that the different electron beams impactadjacent color responsive strips and so that like strips of eachcomponent color responsive section of the series are sequentiallylocated in the path of one of the developed electron beams, applyingmodulation signals of one component color only to each of the developedelectron beams, generating control wave energy, producing phase shiftedvariations of the control energy and applying control wave energy of adifferent phase individually to each of the developed electron beams sothat as all of the beams are deflected relative to the target one onlyis active to cause target luminescence with the other being transverseto the length of the strips of the target and with a relatively slowmotion of deflection being lengthwise of the strips, means fordeveloping control pulses of energy for controlling in sequence thesuppression and the formation of the said electron beams so that duringthe simultaneous deflection of all of the electron beams one only-isinstantaneously active upon one component color response section of thetarget and the sequence of activity and suppression is coordinated witha number of color response strips in the target and means for applyingmodulation signals to the independent electron .beams so that theplurality of electron beams are modulated by signals representative ofone component color for time periods during which action of the relatedcomponent color target area is interrupted.

1 3.' A tricolor additive television system including a cathode ray tubehaving a target area formed of repeating series of elongated stripsadapted individually to luminesce under electron beam impact in each ofthree primary colors of an additive tricolor sequence, means fordeveloping three independent electron beams and for directing the saidelectron beams toward the target area along a plurality of beamprojection paths each angularly disposed relative to a normal to thetarget area and to each other, means for deflecting each of the saidelectron beams relative to the target along bidirectional paths with thedeflection in the direction transverse to the strip elements of thetarget being relatively rapid and the deflection in a directionlengthwise of the target strips being relatively slow, means fordeveloping control wave energy for controlling the time period offormation and suppression of the individual electron beams, saidformation periods being related to the time duration required totransverse, in the direction of rapid motion, the target stripcorresponding to one primary color only of three strips forming eachseries, means to develop three phase shifted variations of the saidcontrol energy to control in a predetermined cycle the periods offormation of electron beams so that during active periods of one beamthe remaining beams are suppressed, means for applying modulationsignals to modulate the electron beams to produce color responses in theprimary color response areas of the targets in accordance with themodulation signals applied and means for adding predetermined incrementsof control energy to the deflection energy to control the rates of beamdeflection for each of the said electron beams to modify the scanningtrace and rate and to provide a substantially orthogonal target tracesfrom each of the scanning beams.

14. In a tricolor television system wherein is included an electron tubehaving a target area formed as a repeating series of elongated stripsadapted to luminesce, under electron beam impact, in three chosencomponent colors of a tricolor additive system, and wherein threedistinct electron beams are developed to impact the target each from adifierent angle relative to each other and each at an acute angle to a.normal to the target, the method of producing additive color imageswhich comprises simultaneously and relatively rapidly deflecting each ofthe developed electron beams across the target area in a directiontransverse to the direction of the elongated strips and relativelyslowly longitudinally of the strips to scan an image raster area,generating a series of three distinct controlling wave energy pulsesfrom the deflection controls for controlling the time periods offormation and suppression of each of the deflected electron beams,shifting the phaseal relationship of each of the control wave energypulses developed from the deflected wave energy so that the severalelectron beams become active in sequence to impact the target area whiletraversing strips of one character in the series and remain inactiveduring remaining periods of deflection transverse to predetermined colorimage producing areas of the target, modulating each electron beam byimage signals representative of one only of the component colors, andsynthesizing the periods of signal application with periods of beamformation and target area impact of the electron beams and resultingcolor response indications on the target area. I

15. A tricolor additive television system including a cathode ray tubehaving a target area formed of repeating series of elongated stripsadapted individually to luminesce, under electron beam impact, in eachof a plurality of primary colors of an additive color sequencmmeans fordeveloping three independent electron beams and for directing the saidelectron beams toward the target area along a plurality of projectionpaths each angularly disposed relative to each other and to a normal tothe impacted target, means for deflecting each of the said electronbeams relative to the target along bidirectional paths with thedeflection in a, direction transverse to the strip elements of thetarget being relatively rapid and the deflection in a directionlengthwise of the target strips being relatively slow, means fordeveloping control wave energy for controlling the time period offormation and suppression of the individual electron beams, said beamsuppression periods being related to the time duration required totraverse each color responsive series of the target in the direction ofrapid motion of the target strip corresponding substantially to of thetime required to traverse the color strips forming each series, whererepresents the number of component colors in the additive series, meansto develop three phase-shifted variations of the control energy tocontrol the developed electron beams with the phase shift between each24 being 21/0 where 0 again represents the number of component colorsand 21 represents the time to traverse one series of color responsestrips, and means for applying modulation signals to modulate theelectron beams to produce color response in the component color responseareas of the targets in accordance with the modulation signals appliedso that signal modulation beams impact 7 the strips in sequence. a

' 16. In a multi-color television system wherein is included an electrontube having a target area formed as a repeating series of elongatedstrips adapted to luminesce, under electron beam im pact,'in the severalcomponent colors of an additive color system, and wherein a plurality ofelectron beams equal in number to the number of component colorproducing strips in the series are developed with each electron beambeing adapted to impact the target, each from a different angle relativeto each other and along a path at an acute angle to a normal to thetarget area, the system for producing additive color imdeflectedelectron beams, means for shifting the 7 phaseal relationship of thedeflected wave energy, pulses developed relative to each other throughan angle of 21r/C where 0 represents the number of component colors inthe multi-color series, so that the plurality of electron beams becomeactive in sequence to impact the target area while traversing strips ofone character in the series and remain inactive during remaining periodsof deflection transverse to predetermined component color imageproducing areas of the target whereby different sections of the targetare impacted by difierent electron beams and color response indications,means to modulate each electron beam by color signals of one colorcomponent only for each beam, and means to synthesize periods of 'beamformation and modulation in desired color so that color responses in theseveral colors are appropriately coordinated.

17. In a tricolor additive television system, a cathode ray imageproducing tube having therein a target area formed from a repeatingseries of luminescent strips adapted to luminesce in each till of threecomponent colors and having means to develop electron beams of a numbercorresponding to the number of component colors of the target area, eachof said beams being of a width substantially equal to the width of eachstrip and of a length substantially equal to the width of three colorstrips, means for deflecting each of the electron beamsrelative to thetarget in bidimensional path traces with a rapid motion of deflectionbeing transverse to the length of the strips of the target and the beamlong dimension and with a, relatively slow motion of deflection in adirection lengthwise of the strips and of the long dimension of thebeam, means for developing control pulses of energy for controlling insequence the suppression and the formation of the said electron beams sothat during the simultaneous deflection of all of the electron beams oneonly is instantaneously active upon one component color response sectionof the target and the sequence of activity and suppression is c0or- 25dinated with a number of color response strips in the target and meansfor applying modulation signals to the independent electron beams sothat the plurality of electron beams are modulated by signalsrepresentative of one component color for time periods during whichaction of the related component color target area is occurred.

18. In a tricolor television system wherein is included an electron tubehavin a target area formed as a repeating series of elongated stripsadapted to luminesce, under electron beam impact, in the severalcomponent colors of a tricolor additive system, and wherein av pluralityof electron beams equal in number to the number of component colorproducing strips in the series are developed with each electron beambeing adapted to impact the target, the method of producing additivecolor images which comprises deflecting each of the developed electronbeams across the laminated target area in a direction transverse to thedirection of the elongated strips. generating controllin wave energy forcontrolling the time of formation and suppression of each of thedeflected electron beams. shifting the phaseal relationship of thedeflected wave image so that the plurality of electron beams becomeactive in sequence upon impacting the target area while traversingstrips of one character in the series and remain inactive duringremaining periods of deflection transverse to predetermined color imageproducing areas of the target whereby different sections of laminationsare impacted by different electron beams and color response indicationson the laminations will appropriately coordinate.

l9. In a tricolor television system wherein is included an electronimage producing tube having a tar et area formed as a repeating seriesof eiongated strips adapted to luminesce. under electron beam impaet, inthe component colors of an additive tricolor system. and wherein anelectron beam is developed within the tube for scanning the componentcolor light producing strips along paths transverse to the length, themethod of producing cyclically additive color images which comprisessupplying modulation signal energy in each of the selected componentcolors to modulate the developed electron beam, a plying biasingvoltages normally tending to nullify the modulation effect of si nalssupplied, generating control wave ener y pulses, producing from thecontrol wave energy pulses a plurality of phase shifted variancesthereof with the phase shift between the ifferent signals beingsubstantially 120 and utilizing the phase shifted variances in. thecontrol wave energy pulses for sequentially overcoming the biasingeffect on each of the impressed component color modulation signals sothat received signals sequentially modulate the developed electron beamand cau e the development of luminescent effects on the target areawhich represent color images in accordance with the ap lied signalenergy.

20. In a tricolor television system wherein is included an electronimage producing tube having a target area formed as a repeating seriesof elon ated strips adapted to luminesce. under electron beam impact, inthe several component colors of an additive tricolor system. and whereinan electron beam, is developed within the tube forscanning the componentcolor light producing strips along paths transverse to the length, a,

system for producing cyclically additive color images which comprisessignal input means for supplying modulation signal energy in each of theselected component colors to modulate the developed electron beam, aplurality of biasing voltage sources connected with the signal input fornormally tending to nullify the modulation effect of signals supplied, acontrol wave energy generating source for producing control pulses,means for producing from the control wave energy pulses a series ofthree phase shifted variances with a substantially like phase shiftbetween each of the difierent pulses and means for supplying theseparate phase shifted variances of the control wave energy pulses tothe signal input for sequentially overcoming the biasing effect oneachof the impressed component color modulation signals so that theinput signals sequentially modulate the developed electron beam anddevelop luminescent effects on the target area in accordance with thecolor representations portrayed by the applied signal energy.

21. In a color television system wherein a color image appears on thetarget area of an electron tube, which target is formed as a repeatingseries of elongated strips adapted to luminesce, under electron beamimpact, in selected and chosen component colors of an additive colorsystem, and wherein a plurality of independently controllable electronbeams equal in number to the number of component colors of the additivesystem are developed and arranged to be focused upon and to impact thetarget each from a different angle relative to each other and each at anacute angle relative to a normal to the target, the combination fordeveloping additive color images which comprises means for relativelyrapidly deflecting each of the developed electron beams across thetarget area in directions transverse to the direction of the elongatedstrips and relatively slowly deflecting each beam longitudinally of thestrips to scan an image raster area, means for deriving energy of afrequency related to the rapid defiection frequency and for generatingfrom such energy a plurality of distinct controlling wave energy pulsesequal in number to the number of separate electron beams for controllingthe time periods of formation and suppression of each of the developedelectron beams, phase shifting means to control the phase relationshipof each of the control wave energy pulses relative to each other so thatthe several electron beams become active in predetermined sequence andfor predetermined'time periods to impact the target area whiletraversing strips of one character only in the series and remaininactive during remain ing periods of deflection transverse topredetermined other color image producin areas of the target, means forsupplying modulating control signals for modulating each electron beamby image signals representative of one only of the selected componentcolors, means for synthesizing the periods of signal modulation withperiods of beam formation and the relationship of the target areaimpacted by the electron beams to provide color response indications onthe target area coordinated with the signal modulation.

22. In a multi-color television system wherein is included an electrontube having a target area formed as a repeating series of elongatedstrips adapted to luminesce, under electron beam impact, in the severalcomponent colors of an additive system, and wherein a plurality ofelectron beams equal in number to the number of component colorproducing strips in the series are developed with each electron beambeing adapted to impact the target, each from a different angle relativeto each other and each along a e 27 .path at an acute angle to a normalto the target area, the system for producing additive color images whichcomprises means for simultaneously and relatively rapidly deflectingeach of the developed electron beams across the strips of the targetarea in a direction transverse to the elongated dimensions of theelongated strips and relatively slowly longitudinally of the strips toscan an image raster area, means for generating controlling wave energypulses for controlling the time periods of formation and suppression ofeach of the deflected electron beams, means for shifting the phasealrelationship of the deflected wave energy pulses developed relative toeach other through an angle of 21r/c, where c represents the number ofcomponent colors'in the multi-color series, so that the plurality ofelectron beams become active in sequence to impact the target area whiletraversing strips of one character in the seriesand remain inactiveduring remaining periods of deflection transverse toother predeterminedcomponent color image producing areas of the target whereby differentsections of the target are impacted by different electron beams andcolor response indications, means to modulate each electron beam bycolor signals of one color component only for each beam, and means tolimit the periods of signal modulation of each electron beam so thatsignal controlled beam modulation occurs only at time periods when thesaid modulated beam impacts sections of the target producing luminescentcolor effects corresponding to those initiating the modulation.

23. A tricolor additive television system including a cathode ray tube.having a target area formed of repeating series of elongated stripsadapted individually to luminesce under electron beam impact, in each ofa plurality of primary colors of an additive color sequence, means fordeveloping three independent electron beams and for directing the saidelectron beams toward the target area along a plurality of projectionpaths each angularly disposed relative to each other and each at anacute angle to a normal to the impacted target, means for deflectingeach of the said electron beams relative to the target alongbidirectional paths with the deflection in a direction transverse to thestrip elements of the target being relatively rapid and at asubstantially uniform rate and the deflection in a direction lengthwiseof the target strips being relatively slow, means for developing controlwave energy for alternately controlling the time period of formation andsuppression of the individual electron beams, said beam suppressionperiods being for time periods of the order of twice the beam formationperiods where the beam formation period corresponds substantially to thetime required to traverse-one of the color strips forming each series,means to develop three substantially 120 phase-shifted variations of thecontrol energy to control in sequence the formation periods of each ofthe electron beams, and means for applying modulation signals tomodulate the electron beams to produce color response in the componentcolor response areas of the targets, in accordance with the modulationsignals applied so that signal modulation beams impact the strips insequence.

24. A color television system comprising an electron tube having abuilt-up target area formed as a repeating series of strip-like elementswith the target elements of each series being of materials adapted tofluoresce upon electron impact in each of a predetermineil Iillmber ofcom- 28 ponent colors to provide additive color images, means tomodulate the deflected electron beam in sequence under control of videosignals representative of each of the selected component colors of theadditive color system to provide intensity control of each colorresponse, means for developing beam control energy having apredetermined relationship to the line frequency at which produced colorimages are to be deflected to limit the periods of active beam response,means to generate from the control energy a series of control pulses outof phase with respect to each other by predetermined amounts and meansfor utilizing the said pulses to control the time periods during whichsignals representative of the several component colors are applied tocontrol the image production.

25. A color television system including an electron tube having includedtherein a target area formed from a plurality of series of strip-likeelements each of a width which is a fractional part of one dimension ofeach image point to be produced and wherein the plurality of strips arecollectively arranged to produce, under excitation by an electronscanning beam, light cheats in each of a predetermined number ofcomponent colors to provide additive color images, means to deflect andconcurrently modulate the electron beam under the sequential control ofseparate video signals equal in number to and representative of each ofthe selected component colors of the additive color system to provide anintensity control of the lightefiects produced in each color, means forderiving electron beam control energy having a predeterminedrelationship to the instantaneously produced color image points, meansto derive from the produced control energy a plurality of controllingsignals to determine the time period during which the sep arate'videosignals are effective individually to control and modulate the saidelectron beam.

26. A color television system comprising an electron tube having atarget area formed as a repeating series of strip-like elements arrangedto be impacted by an electron beam developed within the tube and at timeperiods of electron beam impact to initiate light effects at the pointof impact in a predetermined number of component colors to providecollectively additive color images, means to deflect the electron beamto cause it to trace a scanned raster in a linefor-line manner on thetarget, each line trace of the raster being substantially in a directiontransverse to the long dimension of each striplike element, means tomodulate the deflected electron beam under the control of video signalsrepresentative of each of the selected component colors of the additivecolor system so as to provide intensity control of each color response,means for developing concurrently with the electron beam deflection aseries of control signals bearing a predetermined relationship to theelectron beam deflection in each line as it forms the raster, and meansto utilize the produced control signals to limit the periods of electronbeam modulation by the individual signals and thereby effect a rapidsequential switching of the beam modulation control by the severalcomponent color signals during each traverse of each line of thescanning beam traces forming the image raster so that for each scannedline trace of the image raster light effects representing the producedimage in each selected component color are developed for each scannedelement.

27. Electronic color television apparatus com- 29 prising a cathode raytube having a target area and'having developed therein an electronscanning beam arranged to be deflected in a bidirectional patternrelative to the target area to trace an image raster comprising amultiplicity of elongated coated beam-impact strips each of subelementalwidth as compared to one dimension of each image point to be producedand each secured to form a part of the target area, each of said impactstrips when activated by the impacting electron beam being adapted tocause the production of light in one of a plurality of selectedcomponent colors of an additive color system and collectively arrangedto form substantially uniforrnly repeating sequences of color responseareas so that at least one response in each selected component color isbrought about by electron beam upon its impacting each elemental area ofimage recreation on the image raster, means to deflect the developedelectron beam relative to the beam impact strips to trace the imageraster in a series of substantially parallel lines with the direction ofline production being substantially transverse to the direction of striplength, means for developing electron beam control signal during thetraverse of the scanning 30 beam along each direction of line traverseand transverse to each strip of the target, means to utilize thedeveloped beam control signal energy to limit the instantaneousintensity modulation of the electron beam to the control of a singlecomponent color signal only which is representative of one related andselected component color.

ALFRED N. GOLDSMITH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

